Magnetic-Valve Controllable Transformer-Type Reactors with Phase-by-Phase Reactive Power Control

The article outlines the basic theory, operation principle, peculiarities of electromagnetic processes, and circuit and design solutions of a fundamentally new three-phase magnetic-valve controllable reactor, which combines increased response speed with high-precision stabilization of the current reactive power value. The advisability of a monoblock design with all power elements of the device placed in one transformer-type tank is substantiated. An example of the design of a magnetic-valve controllable transformer-type reactor for a capacity of 25 Mvar, and rated voltage of 35 kV is given along with an analysis of the effectiveness of its three-year operation as part of the Petrovsk-Zabaikalskaya 220/110/35 kV digital substation. It is shown that a reactive power source based on a new magnetic-valve controllable reactor is able---in addition to its main function of optimizing reactive power flows between power supply centers and load nodes---to normalize the voltage quality in a three-phase network with a nonlinear asymmetrical load in terms of such indicators as compensation of slow deviations of the three-phase voltage, symmetry of line-to-line voltages, and elimination of their waveform distortion.

Research on Magnetic-Valve Controllable Reactor Based on ANSYS

Magnetic-valve controllable reactor (MCR) has become many researcher’s topic of the day because of its versatile use in power systems. MCR utilizes the concept of magnetic saturation to control power flows in the power grid. It is as simple to operate and maintain, and reliable as an ordinary transformer. However, magnetic-valve controllable reactor works under a more variety of complex excitation condition because of the superposition action of AC and DC excitations. This paper carefully discusses the distribution of magnetic field of MCR core, provides an understanding of the range of inductance adjustments and further analyzes the working current waveform. Based on that, the finite element analysis software ANSYS Maxwell is used to design and examine a 3-D prototype model under different control voltage levels. The method of transient solution is applied for the reason being that it simultaneously has both AC and DC voltages. The AC voltage is kept constant while the DC voltage is varied from the minimum to the maximum rated value. The simulation results confirm that the magnetic-valve controllable reactor works in the saturation region of the magnetization curve under the combined excitation of AC and DC. The inductance adjustment range shows that the MCR inductance value can be smoothly and continuously varied. In addition, the working output current contains little odd-order harmonics that can be mitigated if filtering device is used or the magnetic valves are designed carefully. By observing the simulation results and analysis, one can gain a thorough understanding of MCR under actual working condition. It provides a reliable basis for the performance design of magnetic-valve controllable reactor.